Railway-traffic-controlling apparatus



April 21, 1931. H. A. THOMPSON 1,802,319

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed July 10, 1928 2& 25

INVENTORZ 17 /3 .Tbampsom Patented Apr. 21, 1931 rr-En STATES HOWARD A. THOMPSON, or enenwoon eonouemrnrmsxnvsnm, nssrenonx'ro THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, ACORPGBA- TZON OF PENNSYLVANIA RAIL'iVAY-TRAIFEG-CQNTROLLING APPARA'JTUS Applicationfiled luly li), 1928. Serial No. 291,505.

My invention relates to railway trafiic controlling apparatus, and particularly to apparatus of the type comprising a plurality of sections. of railway track separated by insulated joints and each provided with governing means controlled by currents separately supplied to the several sections.

One object ofmy present invention is to prevent improper operation of the governing means for one section by current from an adjacent section. I

I will describe three forms of railway traffic controlling apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic view illustratlng one form of railway traffic controlling apparatus eIn-- bodying my invention. Fig. 2 is a diagrammatic view showing a modified form of the apparatus illustrated in Fig. 1, and also embodying my invention. Fig. 3 is a diagrammatic view showing still another form of the apparatus illustrated in Fig. 1 and also embodying my invention. Similar reference characters refer to similar parts in each of the three views.

Referring first to Fig. 1, the reference characters 1 and 1 designate the track rails of a stretch of railway track over which traf- 'fic normally moves in the directionindicated by the arrow. These track rails are divided into a plurality of successive track sections A-B, B-C, etc., by means of insulated joints, designated bythe reference characters 2 and 3 with exponents correspondingto the location, and inserted in thetrack rails 1 and 1*, respectively. Each such track 'section is provided with a source of. unidirectional current here shown as a battery designated by the reference character D withan appropriate exponent. Each battery D is connected in series with aresistanoe 1- across the rails of the corresponding section at the exit end of the section, and the batteries are arranged in such manner that the rails of adjacent sections have opposite polarities. Each track section is further provided with a track relay designated by the reference character R with a suitabledistinguishilig exponent, and connected across the rails adj acent theentrance end of the section,

Located adjacent the entrance end of each section, and controlled by the relay R for the section, is a roadside signal designated by thereference character S with an exponent corresponding to the location. As here shown, these signals are of the type known li 'ht signals each comprising two electric lamps 8 and 9, indicating stop and procoed respectively when lighted; Each signal S is supplied with energy from a battery designated by the reference character E with a sultable exponent, and the supply of this energy is controlled by a contact of the associated relay R. Referring particularly to signal S when relay B is energized, lamp 9 is lighted, and the circuit'for thislarnp passes from battery E through wire 19, front contact 5-5 of relay E wire 18, lamp 9, and wires 17 and 16 back to battery E When'relay B is lo-energized, lamp 8 is lighted, and the circuit for lamp 8 passes from battery E hrough wire 19, back 0011- tact 55" of relay R wire 21, lamp 8, and 'w1res-2O and 16 back to battery E As shown in the drawing, section A-B and the section to the right of point C are unoccupied, but a train indicated diagrammatically at V, occupies section B-C. Re-

lays R and R are therefore energized so that signals S and S indicate proceed,but relay R is die-energized because the axles of train V shunt theQenergy away from the relay',- and signal S accordingly indicate t p 77 s v With theapparatusthus' far described, a dangerousfcondition might exist should one or both oft-he insulated j'oints'fl, 3 break down at the entrance to an occupied section,

thereby permitting current fromthe adjacent section to energizethe'track relay for such occupiedsection. For example, I will 'assume'that joint 2 breaks" down. Under these conditions current might flow from battery D through wire 22', rail -1"of section A413, will of section BC,wires 23 and 24, winding of relay-R wires 25, 26, and 27 to rail 1* of section B-C, thence through the ground arounclinsulated joint 3 to ra'i1 1 might, under some conditions, be so low that the current supplied to'relay B would be of suflicient magnitude to pick up the relay. In 1 similar manner should insulated joint 3 break down, current might flow from battery D through wire 22, rail 1 of section A-B, thence through the ground around insulated joint 2 to rail 1 of section BC, through wires 23 and 24. the winding of relay R wires 25, 26, and 27, rail 1* of section B-C to rail 1* of section A-B through joint'3 andiso-through wire 28, resistance, and wire 29 back tobattery D Should insulated joints 2 and 3 both break down this condition would be exaggerated, for under these conditions, battery D would be connected directly across relay R through resistance 4. In any of these cases, therefore,

it will be manifest that should an insulated joint break down and cause improper oper ation of relay R signal S would indicate glgced even though a train occupies section To prevent improper operation of the apparatus under the foregoing conditions, I connect in multiple with'each relay Ran asymmetric unit designated by the reference character 7 with an exponent corresponding to the location. Each asymmetric unit 7 is arranged in such manner that current of the polarity normally supplied to the track section to which each relay is connected will not flow through the unit, but current of the opposite polarity will flow through the unit. I also interpose between each asymmetric unit 7 and each track relay R another asymmetric unit 6, the units 6 being so disposed that a low resistance is offered to current of the polarity normally supplied to the relay, but a high resistance is offered to current of opposite polarity. It will be apparent, therefore, that with the units arranged in this manner, if an insulated joint breaks down between a forward section which is occupied and an adjacent rear section, so that the forward section is supplied with current from the rearsection, the track relay for the forward section will not become energized by the current from the rear section, because the unit 7 associated with the relay will shunt such current away from the relay, and the unit 6 will offer a high resistance to the flow of current through the relay. F nrthermore, with the units arranged in this manner, if one of the units fails, the failure will generally be readily detected, and in case it is not detected, the other unit will continue toprotect the relay. For example, if unit 7 should become short circuited, or unit 6 open-circuited, the associated relay R will fail to become energized when the section with which it is connected is unoccupied, and the failure will therefore be detected. If unit 7 should becomeopen-circuited, unit 6 willastill protect the relay, and if unit 6 should become short circuited unit 7 will protect the relay.

In the modification shown in Fig. 2, apparatus includes in addition to the signaling circuits shown in Fig. 1, means for supplying at times alternating train controlling current to the rails of each track section, which current is furnished by a generator G connected with line wires 34 and 35. This train controlling current is applied to the track rails of each section by a transformer designated by the reference character T with an exponent corresponding to the location the secondary of which transformer is connected'in series with a reactance 11 between the track battery D and the resistance 4 for the section. The primary circuit for each transformer T is controlled by a front contact l010" of the track relay R for the section next in advance, such primary the transformer L, the primary 33 of which is connected across the line wires 34 and It will be seen, therefore, that alternating train controlling current is applied to the track rails of each section except the section in the rear of any occupied section. The alternating train controlling current thus supplied to the rails may be used to control train carried governing means in any suitable maner. In one form of train carried governing means suitable for cooperation with the trackway apparatus here shown, a proceed indication is received on board the train when train con; trolling current is being supplied to the rails, but a stop indication is received on board the train when no train controlling current is being supplied to the rails.

Referring now particularly to the appara- 7 tus located at point B, the asymmetric units 6 and 7 are so disposed that current of the polarity normally supplied to therails of section BC by battery D is permitted to flow in the winding of relay R but current of the opposite polarity inthe rails of section B.C is prevented from flowing through the winding of relay R I will now assume that either or both of insulated joints 2 or 3 break down, If section B C is unoccupied when this occurs, so that relay R is energized, the rails of section BC might then be supplied with both unidirectional current from battery rent, however, might flow in the winding of relay R? during alternate half-cycles. In order to prevent this Occurrence, I construct the parts in such manner that the maximum electromotive force of the transformer-YT is less than the electromotive force of battery D With this arrangement, the resultant current supplied from section AB to relay R always has the same polarity, although the current contains an alternating component. This resultant current is prevented from flowing throughrelay R and the relay therefore opens. The circuit for primary 31 of transformer T is then open at contact 10-10, and under these conditions, the rails of section AB are supplied with unidirectional current only. As a result, the only means forperiodically varying the train current which mightnow be supplied to the rails of section BC from section AB due to a broken down insulated joint will be unidirectional current from battery D and the relayR will therefore be protected from im proper operation byasymmetric units 6 and 7 It will be manifest, therefore, that with the apparatus arranged in the manner shown in Fig. 2, it is impossible for relay R to 'become improperly energized by stray currents supplied to the relay due to a broken down insulated joint, and so itis impossible for a train to receive a proceed indication when 'a stop indicaton should be receved.

Referring now to Fig. 3, Ihave shown associated with each track section a line relay which is designated by the reference charac ter F with anexponentcorresponding to the location, and whichis supplied with current from a battery E over a back contact 3670f the relay R for the section whenever the relay R for the section is de-en'ergized; Referring particularly to section BC,'when line relay F is energized and when track rei lay R is de-energized train controlling current is supplied'to the primary 31 of transformer Tc, over a circuit which passesfrom secondary 32 of the line transformer L through wire 47, front contact 12 of relay F 2 wires 40 and 41, contact 14, wire 42, front 7 contact 101O of relay B wire 44, primary 31 of transformer T and wires 45 and 46 back to secondary 32 of transformer L When line relay F is energized and when trackrelay R is de-energized, train controlling current is then supplied to the primary 31 of transformer T olver another circuit which passes from secondary 32 of transformer L through wire 47, front contact 12 of relay F wire 40, contact 13, wire43, back contact 101O of relay R ,wire 44, primary 31 0f transformer T and wires'45 and 46 back to secondary 32 of transformer L The train controlling current supplied to the track rails by transformer T may be pe riodically varied by means of cams O and O which are driven at constant speed by means of a motor supplied with current from secondary 32 of transformer L over front contact 12 of relay F when relay F'is energized. The cam'O operates the contact 14 for supplying high speed or proceed code to the rails of the section, and the cam O controlsthe contact 13 for supplying low speed or stop code to the rails of the section. High speed code-can only be supplied when relays F and R are both energized, and

low speed code can only be supplied when relay F is energized and relay R is de-energiz'ed, The trackway apparatus here shown is suitable for cooperation with, train carried governing means which are selectively responsive in any "suitable manner to the variations in the train controlling current. It isunderstood that although I have shown governing current at two rates, my invention is not limited to this number.

WVith the apparatus-constructed in the foregoing manner, ajtrain entering section AB while section B'C is occupiednore' from seetionAB, due to a brokendown insulated joint at point B, is preventedfrom flowingin the winding of relay R3 to energize the relay, andalterna-ting current supplied to section BO from section A-B underthe same conditions, is also prevented from flowing in the winding'of relay R during the alternate half cycles in which the current has the same polarity as the polarity of the unidirectionalcurrent supplied by section To prevent'alternating current from section A-B from flowing in the relay winding during the remaining half cycles, I construct the secondary 30 of transformer T insuch manner that the maximum electromotive force at its terminals at any instant is less than the electromotive. force of bat- "tery D With the parts arranged in this manner, the current which'might be supplied to section BC from section A'B always fiows'in such a direction'that asymmetric units 6 and 7 will prevent this current from energizingthe relay R ,-and a dangerand modifications may be made therein within the scope of the appended claims, Without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a forward and a roar section of railway track separated by insulated joints in the track rails, a source of unidirectional current connected with the rails of the forward section, a track relay connected with the rails of the forward section, a source of unidirectional current connected with the rails of the rear section in such manner that the polarity of the rails of the rear section is opposite to the polarity of the rails of the forward section, means associated with said relay for preventing the relay from being energized by current from the rear section if an insulated joint breaks down but not interfering with the normal operation of the relay due to current normally supplied to the rails of the forward section, and traffic governing means controlled by said relay.

2. In combination, a forward and a rear section of railway track separated by insulated joints in the track rails, means for separately supplying the rails of said sections with unidirectional current in such manner that the polarity of the rails of the forward section is opposite to the polarity of the rails of the rear section, a track relay connected with the rails of the forward section, anasymmetric unit associated with said relay and arranged to permit current from the forward section to flow through the relay but to prevent current from the rear section from flowing through the relay if an insulated joint breaks down, and traflic governing means controlled by said relay.

3. In combination, a first and a second section of railway track separated by insulated joints in the track rails, means for separately supplying the rails of said sections with unidirectional current in such manner that the polarity of the rails of the first section is opposite to the polarity of the rails of the second section, a track relay connected with the rails of the first section, an asymmetric unit interposed between said relay and a track rail for reventing current from the mond section rom flowing through said relay if one of said insulated joints breaks down, and traflic governing means controlled by Said relay.

4. In combination, a first and asecond section of railway track separated by insulated joints in the track rails, means for separately supplying the rails of said sections with unidirectional current in such manner that the polarity of the rails of the first section is opposite to the polarity of the rails of the second section, a track relay connected with the rails of the first section, an asymmetric unit connected in multiple with the relay for shunting the relay if current is supplied to the relay from the second section due to a broken down insulated joint, and traific governing apparatus controlled by said relay.

5. In combination, a first and a second section of railway track separated by insulated joints in the track rails, means for separately supplying the rails of said sections with unidirectional current in such manner that the polarity of the rails of said first section is opposite to the polarity of the rails of said second section, a track relay connected across the rails of said first section, a first asymmetric unit connected in multiple with said relay to shunt current from said relay if current is supplied to said first section from said second section due to a broken down insulated joint, a second asymmetric unit interposed between said relay and said first asymmetric unit for preventing current from said second section from flowing through said relay if said first asymmetric unit fails, and traffic governing apparatus controlled by said relay.

6. In combination, a forward and a rear section of railway track separated by insulated joints in the track rails, a first source of unidirectional current, a first source of train controlling current connected in series with said first source of unidirectional current across the rails of said forward section, a second source of train controlling current, a second source of unidirectional current, means including said second source of train controlling current for connecting said second source of unidirectional current across the rails of said rear section in such manner that the polarity of the unidirectional current supplied to the rails of the rear section is opposite to the polarity of the unidirectional current supplied to the rails of the forward section, a track relay connected with the rails of the forward section, asymmetric units associated with said relay for preventing said relay from being energized by current from said second source of unidirectional current if an insulated joint breaks down, and trailic governing apparatus controlled by said relay.

7. In combination, a first and a second section of railway track separated by insulated joints in the track rails, a source of unidirectional current connected with the rails of the first section, a track relay connected with the rails of the first section, a source of unidirectional current connected with the rails of the second section in such manner that the polarity of the rails of the first section is opposite to the polarity of the rails of the second section, a transformer having its secondary interposed between said second source and a track rail, means controlled by a front contact of said relay for at times supplying the primary of said transformer with train con- I11 trolling current, asymmetric units associated with said relay for preventing the relay from being energized by current that might be supplied to the first section by the second source if an insulated joint broke down, and traific governing means controlled by said relay.

8. In combination, a first and second adjacent sections of railway track separated by insulated joints in the track rails, a first source of unidirectional current connected with the rails of the first section, a track relay connected with the rails of the first section, a second source of unidirectional current connected with the rails of the second section and arranged in such manner that the rails of the first section are of opposite polarity from the rails of the second section, an asymmetric unit connected in multiple with said relay and arranged to offer a high resistance to the current supplied to the relay by the first source but to offer a low resistance to current that might be supplied to the relay by the second source if an insulated joint broke down, means for supplying the rails of the second section with train controlling current when said relay is energized but for disconnecting said supply when said relay is die-energized, and trafiic vgoverning means controlled by said relay.

9. In combination, a first and second adjacent sections of railway track separated by insulated joints in the track rails, a first source of unidirectional current connected with the rails of the first section, a second source of unidirectional current connected with the rails 01": the second section and arranged in such manner that the adjacent rails in the two sections have opposite polarities, a track relay connected with the rails of the first section, a first asymmetric unit interposed between said relay and a track rail and arranged to ofier a low resistance to current supplied to the relay by the first source but a high resistance to current that might be supplied to the relay from the second source it an insulated joint broke down, an asymmetric unit connected in multiple with the first asymmetric unit and the relay and arranged to shunt current from the relay if the relay is supplied with current of a polarity opposite to that supplied by the first source, means controlled by the relay for at times supplying the second section with train c011- trolling current, and traific governing mean controlled by said relay.

10. In combination, a first and a second section of railway track separated by insulated joints in the track rails, a source of unidirectional current connected with the rails of the first section, a first relay connected with the rails of the first section, a second relay connected with the rails of the second section, a transformer, a second source of unidirectional current connected across the rails of the second section in series with the secondary of said transformer and arranged in such manner that the polarity of the rails of the firstsection is opposite to the polarity of the rails of the second section, a line relay controlled by a back contact of said second relay, means controlled by the line relay for at times supplying the primary of said transformer with train controlling current which is periodically varied at one frequency when the first relay is energized but which is periodically varied at another frequency when the first relay is de-energized, asymmetric units associated with said first relay for preventing said first relay from being energized by current from the second section if an insulated joint breaks down when the first section is occupied, and tratfic governing means controlled by said first relay.

In testimony whereof I aifix my signature.

HOWARD A. THOMPSON. 

